1. Field of the Invention
The present invention relates to window assemblies for buildings, and in particular to mounting glazing units within window frames of such window assemblies. More specifically it relates to packing arrangements for fitting between the glazing unit and frame of a window assembly to support the glazing unit within the window frame.
2. Related Art
Windows comprise a glazing unit mounted within a surrounding frame. The glazing unit is typically a sealed double glazing unit comprising two parallel spaced apart panes of glass joined and sealed around their edges to enclose a space between the panes. The frame is made up from a number of sections, joined together at their ends and the corners of the frame. The frame may be made from wood, metal, or more commonly now plastic, for example uPVC. The inside edge of the frame defines a rebate to receive the glazing unit within the frame with the frame surrounding the glazing unit.
The frame and glazing units are manufactured separately, and must be matched so that the glazing unit fits within the frame. However due to manufacturing variability and tolerances, and to enable the glazing unit to be fitted into the frame, there is a varying clearance (typically up to 6 mm) between the glazing unit and frame. Accordingly in order to securely locate and fix the glazing unit within the frame, spacers or packing elements are fitted between the edges of the glazing units and frame. The spacers and packing elements are arranged take up the clearances between the frame and glazing unit to locate the glazing unit and wedge the glazing unit within the frame. In addition to locating the glazing unit within the frame, this also stiffens the frame and window assembly.
Conventionally such spacers or packing elements comprise pairs of wedges which are located between the glazing unit and frame. Each pair of wedges is arranged with their inclined surfaces overlying each other along the edge of glazing unit and within the plane of the glazing unit and frame. In use the wedges are slid relative to each other laterally parallel to plane of the window and along the edge of the glazing unit such that one wedge and inclined surface rides up over the other increasing the overall height of the overlying wedges and taking up the clearance between the glazing unit and frame. An example of such an arrangement is described in GB 2,251,261 A. GB 2,314,265 A shows (FIG. 3) a similar variable thickness packing arrangement comprising two angled wedges, although this patent is directed to door panels.
While such packing arrangements function adequately, the pairs of wedges are relatively difficult to fit between the glazing unit and frame. In addition it is relatively difficult and awkward to get access to the wedges to slide them laterally along the edge of and between the glazing unit and frame. Furthermore the glazing unit must be held in place within the frame until and whilst the wedges are slid to take up the clearance between glazing unit and frame to secure the glazing unit in place. This makes assembly difficult in particular for a single installer.
Alternative packing and spacing arrangements, and in particular packing elements to be fitted between the glazing unit and frame, are described in EP 0716206 and EP 0599051. These packing elements comprise a panel having a resilient projecting arcuate bulge oriented transversely to the panel and edge of the glazing unit. The packing element is fitted into the frame and the glazing unit then installed with the edge of the glazing unit riding up over and compressing the arcuate bulge. The clearance, and any variation in clearance, between the glazing unit and frame is taken up by the resilience and deformation of the arcuate bulge. Such packing elements can however only accommodate a limited variation in clearance between the glazing unit and frame and can be improved upon.
Various other glazing packing arrangements are described, for example, in:
GB 1,537,289, which describes the use of spacer elements comprising incompressible spacer blocks;
GB 1,150,807, which also shows the use of setting blocks to space the glazing unit form the frame;
GB 2,344,846, which a glazing packing arrangement which has an extension to secure and space a window bead;
EP 1,288,427, which describes an L shaped spacer block in which an arm of the spacer also holds the frame in the frame; and
GB 2,309,248, which also descries an L shaped bead retaining spacer, but which in this case also shows flexible elements which engage and seal against the surface of the window pane.
It is also known to provide fixing member which engage the glazing unit to secure the glazing unit within the window frame. Such fixing member typically comprise upstanding projecting flanges, typically two spaced apart flanges between which an edge of the glazing unit is fitted with the flanges abutting the surfaces of the glazing unit. These fixing members may extend along the entire edge of the glazing unit and also act a water seal. Examples of such arrangements are described, for example, in U.S. Pat. No. 4,006,569, U.S. Pat. No. 4,640,072, and GB 2,279,687. GB2,212,545 also describes the use of a fixing member, but which this time is L shaped and includes on one upstanding flange.
It is desirable to provide an improved arrangement for mounting glazing units within window frames which addresses the above described problems and/or more generally offers an improvement and/or alternative to existing arrangements.